Field of the Invention
The present invention relates to a technology for use in a web browser in which a data storage mechanism in a web browser supporting Hyper Text Markup Language (HTML) 5 is implemented.
Description of the Related Art
As the function of a web application highly improved, various functions are extended in HTML5. An example of the extended functions is the FileSystem Application Programming Interface (API) function for operating a FileSystem in a storage area of a web browser. The FileSystem API function allows a user to handle a large file of, for example, a document, a moving image, and a game. In addition to the FileSystem API function, an application cache function for caching a file on a web server and a WebStorage function and an IndexedDataBase (IndexedDB) function for storing data in a storage area for a web browser are available. In addition, a mechanism for managing a state of connection (online/offline) between an information processing terminal, on which a web browser operates, and a network is provided to allow a web application to reference the state and to notify a web application of a change in the state.
These extended functions enable a personal computer (PC) and a mobile terminal, which browse a web application (web site), to use a service available on the web site by using a file or data stored in a storage area for the web browser, even when the PC and the mobile terminal are offline.
On the other hand, there is a conventional technology for caching contents provided by a web site, to a storage area of a web browser. In addition, some web browsers provide a Graphical User Interface (GUI) for allowing the user to delete cached data.
As a method for deleting unnecessary cached data, there is a conventional technology discussed in Japanese Patent Application Laid-Open No. 2009-70373. The technology discussed in Japanese Patent Application Laid-Open No. 2009-70373 is that a web application is registered in an image formation apparatus, a required file is cached when the web application is used, and the related cache is deleted when the registration of the web application is deleted.
Because the extended functions described above allow a very large file to be saved in a storage area for a web browser as compared with a cache of a conventional web browser, there is an issue that a large amount of storage capacity of the terminal is used for that file. In the technology discussed in Japanese Patent Application Laid-Open No. 2009-70373, when a user deletes a web application, it can be easily determined that the web application is not necessary and, therefore, there is no problem if the related cache data is deleted. However, the operation to browse or close a web site on a web browser is significantly different from the operation to register or delete (installation or uninstallation) of a web application. That is, just because of the operation performed to close a web site via a web browser or to terminate a web browser, it cannot be determined whether the web site will not be used in the future. This means that the technology discussed in Japanese Patent Application Laid-Open No. 2009-70373 does not solve the above issue caused by the extended functions described above.